PROJECT SUMMARY Excessive weight gain among young adult women age 18-35 years is an alarming and overlooked trend that must be addressed to reverse the epidemics of obesity and chronic disease. During this vulnerable period women tend to gain disproportionally large amounts of weight compared to men and other life periods. Our team developed a lifestyle modification intervention (HEALTH) that prevented weight gain, promoted sustained weight loss, and reduced waist circumference in partnership with Parents as Teachers (PAT), a national home visiting, community based organization with significant reach in this population. PAT provides parent-child education and services free-of-charge to nearly 170,000 families through up to 25 free home visits per year until the child enters kindergarten. This study will extend these findings by extends our previous work with a pragmatic cluster randomized controlled trial to evaluate dissemination and implementation of HEALTH across three levels (mother, parent educator, PAT site) to achieve widespread impact. We will conduct a pragmatic cluster randomized controlled trial to evaluate HEALTH and the HEALTH training curriculum (implementation strategy) on weight among mothers with overweight and obesity across the US (N= 252 HEALTH; N= 252 usual care). Parent educators from 28 existing PAT sites (14 HEALTH, 14 usual care) will receive the HEALTH training curriculum through the PAT National Center, using PAT?s existing training infrastructure, as a continuing education opportunity. An extensive evaluation, guided by RE-AIM will determine implementation outcomes (acceptability, adoption, appropriateness, feasibility, fidelity, and adaptation) at the parent educator level. The Conceptual Framework for Implementation research will characterize determinants that influence HEALTH dissemination and implementation at three levels: mother, parent educator, PAT site to enhance external validity (reach and maintenance) and population level impact. The findings from this innovative study will have significant potential to help reverse the trend of excessive weight gain among young adult women, a critical priority target in battling the epidemics of obesity and chronic disease, by reaching women with an evidence-based intervention nation-wide.